Communication device and resource reallocation method in radio communications system

Abstract

A resource reallocation method that can suppress variations in reception delay time in reservation-type scheduling and a communication device using the method are provided. In a radio communications system in which a radio resource is reserved to periodically perform a communication between communication devices, the number of retransmissions of a packet transmitted to a communication device using the reserved radio resource (Step S 201 ) is measured (Step S 203 ), and reallocation of a radio resource to be used for the communication is performed depending on the number of retransmissions (Steps S 204 and S 205 ).

1 . A resource reallocation method in a radio communication system in which a radio resource is reserved to periodically perform a communication between communication devices, comprising:
 counting the number of retransmissions of a packet transmitted to a first communication device using a reserved radio resource; and   reallocating a radio resource for a first communication with the first communication device depending on the number of retransmissions.   
     
     
         2 . The resource reallocation method according to  claim 1 , wherein when the number of retransmissions is equal to or greater than a predetermined value, a different radio resource having at least one of a different transmission timing and a different frequency from the reserved radio resource is reallocated for the first communication. 
     
     
         3 . The resource reallocation method according to  claim 2 , wherein the different radio resource has the different frequency at a same transmission timing. 
     
     
         4 . The resource reallocation method according to  claim 3 , wherein the different radio resource having the different frequency at a same transmission timing is an unreserved radio resource. 
     
     
         5 . The resource reallocation method according to  claim 3 , wherein when the different radio resource having the different frequency at the same transmission timing is a radio resource reserved for a second communication with a second communication device, and number of retransmissions for the second communication is equal to or greater than the predetermined value, respective radio resources are exchanged between the first and the second communications. 
     
     
         6 . The resource reallocation method according to  claim 2 , wherein the different radio resource has the different transmission timing. 
     
     
         7 . The resource reallocation method according to  claim 6 , wherein the different radio resource having the different transmission timing is an unreserved radio resource. 
     
     
         8 . The resource reallocation method according to  claim 6 , wherein when the different radio resource having the different transmission timing is a radio resource reserved for a second communication with a second device, and the number of retransmissions for the second communication is is equal to or greater than the predetermined value, respective radio resources are exchanged between the first and the second communication. 
     
     
         9 . The resource reallocation method according to  claim 5 , wherein the reserved radio resource for the first communication and the reserved radio resource for the second communication have the same amount. 
     
     
         10 . The resource reallocation method according to  claim 5 , wherein the reserved radio resource for the first communication and the reserved radio resource for the second communication have different amounts. 
     
     
         11 . A communication device in a radio communication system that reserves a radio resource to periodically perform a communication with a first communication device, comprising:
 a retransmission frequency measurement section configured to count the number of retransmissions of a packet transmitted to the first communication device using a reserved radio resource; and   a resource reallocation section configured to reallocate a radio resource for a first communication with the first communication device depending on the number of retransmissions.   
     
     
         12 . The communication device according to  claim 11 , wherein when the number of retransmissions is equal to or greater than a predetermined value, the resource reallocation section configured to reallocate a different radio resource having at least one of a different transmission timing and a different frequency from the reserved radio resource for the first communication. 
     
     
         13 . The communication device according to  claim 12 , wherein the different radio resource has the different frequency at a same transmission timing. 
     
     
         14 . The communication device according to  claim 13 , wherein the different radio resource having the different frequency at the same transmission timing is an unreserved radio resource. 
     
     
         15 . The communication device according to  claim 13 , wherein when the different radio resource having the different frequency at the same transmission timing is a radio resource reserved for a second communication with a second communication device, and number of retransmissions made for the second communication is equal to or greater than the predetermined value, the resource reallocation section configured to exchange respective radio resources between the first and the second communications. 
     
     
         16 . The communication device according to  claim 12 , wherein the different radio resources has the different transmission timing. 
     
     
         17 . The communication device according to  claim 16 , wherein the different radio resource having the different transmission timing is an unreserved radio resource. 
     
     
         18 . The communication device according to  claim 16 , wherein when the radio resource having the different transmission timing is a radio resource reserved for a second communication with a second communication device, and the number of retransmissions for the second communication is is equal to or greater than the predetermined value, the resource reallocation section configured to exchange respective radio resources between the first and the second communications. 
     
     
         19 . The communication device according to  claim 15 , wherein the reserved radio resource for the first communication and the reserved radio resource for the second communication have the same amount. 
     
     
         20 . The communication device according to  claim 15 , wherein the reserved radio resource for the first communication and the reserved radio resource for the second communication have different amounts. 
     
     
         21 . A base station in the radio communications system, comprising the communication device according to  claim 11 . 
     
     
         22 . A radio communications system including at least one base station and at least one mobile terminal wherein a radio resource is reserved to periodically perform a communication between a base station and a mobile terminal, wherein
 the base station comprises:   a retransmission frequency measurement section configured to count the number of retransmissions of a packet transmitted to a first motile terminal using a reserved radio resource; and   a resource reallocation section configured to reallocate a radio resource for a first communication with the first mobile terminal depending on the number of retransmissions.   
     
     
         23 . The radio communications system according to  claim 22 , wherein when the number of retransmissions is equal to or greater than a predetermined value, the resource reallocation section configured to reallocate a different radio resource having at least one of a different transmission timing and a different frequency from the reserved radio resource for the first communication. 
     
     
         24 . A computer readable information recording medium storing a program which, when executed by a processor in a communication device in a radio communications system that reserves a radio resource to periodically perform a communication with a first communication device, performs a method comprising:
 counting the number of retransmissions of a packet transmitted to the first communication device using a reserved radio resource; and   reallocating a radio resource for a first communication with the first communication device depending on the number of retransmissions.   
     
     
         25 . The computer readable information recording medium according to  claim 24 , wherein when the number of retransmissions becomes is equal to or greater than a predetermined value, a different radio resource having at least one of a different transmission timing and a different frequency from the reserved radio resource is reallocated for the first communication.